Azurins, a wild type and a genetically mutant K27 altered one, were immobilized on annealed gold surface and investigated by means of atomic force microscopy. It was found that the surface coverage and height distribu...Azurins, a wild type and a genetically mutant K27 altered one, were immobilized on annealed gold surface and investigated by means of atomic force microscopy. It was found that the surface coverage and height distribution of the adsorbed protein molecules are different from each other, which is possibly the result of the different orientation on the surface. It is believed that the wild type azurin is connected to gold surface by the disulphide bridge; while the mutant, K27C, might be through the thiol groups of the cysteine residues on their surface.展开更多
Site-directed spin labeling (SDSL) is a powerful tool for monitoring protein structure, dynamics and conformational changes. In this study, the domain-specific properties of azurin and its interaction with p53 were st...Site-directed spin labeling (SDSL) is a powerful tool for monitoring protein structure, dynamics and conformational changes. In this study, the domain-specific properties of azurin and its interaction with p53 were studied using this technique. Mutations of six residues, that are located in the hydrophobic patch of azurin, were prepared and spin labeled. Spectra of the six azurin mutants in solution showed that spin labeled residues 45 and 63 are in a very restricted environment, residues 59 and 65 are in a spacious environment and have free movement, and residues 49 and 51 are located in a relatively closed pocket. Polarity experiments confirmed these results. The changes observed in the spectra of spin labeled azurin upon interaction with p53 indicate that the hydrophobic patch is involved in this interaction. Our results provide valuable insight into the topographic structure of the hydrophobic domain of azurin, as well as direct evidence of its interaction with p53 in solution via the hydrophobic patch. Cytotoxicity studies of azurin mutants showed that residues along the hydrophobic patch are important for its cytotoxicity.展开更多
Enzymatic activities are important to be quantified in products as enzymatic cleaners, which are used in medical and surgical devices reprocessing. Enzymatic activities are critical for the proper chemical cleaning th...Enzymatic activities are important to be quantified in products as enzymatic cleaners, which are used in medical and surgical devices reprocessing. Enzymatic activities are critical for the proper chemical cleaning that intends to remove solid organic dirt from inaccessible sites. The most important enzyme for this purpose is the protease, which is able to dissolve the main dirt attached to medical and surgical instruments. In this context, this study contributes to the development of a new proteolytic activity quantification method and its validation. The methodology is based on colorimetry and uses a UV-Vis spectrophotometer to measure the substrate hydrolysis by the blue color intensity, employing Protazyme AK tablets as substrate.展开更多
文摘Azurins, a wild type and a genetically mutant K27 altered one, were immobilized on annealed gold surface and investigated by means of atomic force microscopy. It was found that the surface coverage and height distribution of the adsorbed protein molecules are different from each other, which is possibly the result of the different orientation on the surface. It is believed that the wild type azurin is connected to gold surface by the disulphide bridge; while the mutant, K27C, might be through the thiol groups of the cysteine residues on their surface.
基金supported by the National Natural Science Foundation of China (Grant No. 30370361)the National Basic Research Program of China (Grant No. 2006CB500700)supported by the Key Laboratory of Mental Health, Chinese Academy of Sciences
文摘Site-directed spin labeling (SDSL) is a powerful tool for monitoring protein structure, dynamics and conformational changes. In this study, the domain-specific properties of azurin and its interaction with p53 were studied using this technique. Mutations of six residues, that are located in the hydrophobic patch of azurin, were prepared and spin labeled. Spectra of the six azurin mutants in solution showed that spin labeled residues 45 and 63 are in a very restricted environment, residues 59 and 65 are in a spacious environment and have free movement, and residues 49 and 51 are located in a relatively closed pocket. Polarity experiments confirmed these results. The changes observed in the spectra of spin labeled azurin upon interaction with p53 indicate that the hydrophobic patch is involved in this interaction. Our results provide valuable insight into the topographic structure of the hydrophobic domain of azurin, as well as direct evidence of its interaction with p53 in solution via the hydrophobic patch. Cytotoxicity studies of azurin mutants showed that residues along the hydrophobic patch are important for its cytotoxicity.
文摘Enzymatic activities are important to be quantified in products as enzymatic cleaners, which are used in medical and surgical devices reprocessing. Enzymatic activities are critical for the proper chemical cleaning that intends to remove solid organic dirt from inaccessible sites. The most important enzyme for this purpose is the protease, which is able to dissolve the main dirt attached to medical and surgical instruments. In this context, this study contributes to the development of a new proteolytic activity quantification method and its validation. The methodology is based on colorimetry and uses a UV-Vis spectrophotometer to measure the substrate hydrolysis by the blue color intensity, employing Protazyme AK tablets as substrate.
